A virtual warehouse is an information system concept, not a physical location. It aggregates inventory data from multiple physical locations—such as different distribution centers, retail stores, and in-transit stock—into a single, unified database. This creates a holistic and real-time view of all available inventory across the entire network. This "connectedness" through information technology provides the high level of visibility and control necessary for an organization to have confidence in its distribution system's ability to meet demand efficiently.

A. Commodity warehouse: This refers to a physical facility used for storing bulk, undifferentiated goods (e.g., grain, oil). It describes a type of warehouse, not a concept of network connectedness.

B. Allocation warehouse: This describes a functional process within a physical warehouse where goods are pre-assigned to specific orders or destinations, not an overarching system for network confidence.

D. Implicit warehouse: This is not a standard or recognized term within supply chain management literature and does not describe a valid concept for managing a distribution system.

1. Rushton

A.

Croucher

P.

& Baker

P. (2022). The Handbook of Logistics and Distribution Management (7th ed.). Kogan Page. The concept is discussed in the context of e-fulfillment and inventory management

where a virtual warehouse provides a "single view of stock" across multiple locations to improve availability and customer service (Chapter 13

E-commerce and Omni-channel).

2. Frazelle

E. (2016). Supply Chain Strategy: The Logistics of Supply Chain Management. McGraw-Hill. Frazelle discusses "virtual inventory" as a strategy where information is used to substitute for physical inventory

creating a connected system with higher visibility and confidence without physically centralizing all stock.

3. MIT OpenCourseWare. (2016). 15.762 Supply Chain Planning. Massachusetts Institute of Technology. Course materials on inventory management discuss concepts like risk pooling

where inventory is logically centralized (or virtualized) to manage demand uncertainty

which directly relates to maintaining confidence in the distribution system's performance. Available at: https://ocw.mit.edu/courses/15-762-supply-chain-planning-spring-2016/